\pgfdeclareshape{radialstub}{\anchor{center}{\pgfpointorigin}
  \behindforegroundpath{
    \pgfscope
      \pgfstartlinewidth=\pgflinewidth
      \pgfsetlinewidth{\pgfkeysvalueof{/tikz/circuitikz/bipoles/thickness}\pgfstartlinewidth}
      \pgfpathmoveto{\pgfpointorigin}
      \pgfpathlineto{\pgfpointpolar{30}{6mm}}
      \pgfpatharc{30}{150}{6mm}
      \pgfpathclose
      \pgfusepath{draw}
    \endpgfscope
  }
}
